Turbine blading



ROLAND MARSLAND, or. nssmdroii, innivsytvaiim, Assieivon'ro,wnsrrnentonsn nnno'lrnrojlenn MANnFAoTURiNGcoi/rrnnr, A conoRA'rIoN or rnNNsYLvANrA.

v i TURBrNn BLADING.

Application vfiledI "September 18, 19213. Serial No. 663,435,...` i

'My .invention relates to" turbine `blading and it has 4for its object to providefasten l `ings or root vconnections thereforwhich are suitable yfor securing blades of the larger type toa rotor. t

A further Vobject 'of my 'invention' is to provide a rotor having a plurality `of circumferential groovesjfor blades, each of which is provided'with a plurality 'of root exhaust' type of blading shown, described and claimed in thel patent to Baumanmreissued April 26,' 1921, 'No f15,092, for 'the reason that the sidewalls of a wide groove for blading of this typewould'be stressed beyond the allowable limit. It hasbeen` proposed to secureblading of this type vto a rotor by having Athe root portionsl of the blades Veach provided with a plurality of tongues which fit-circumferential grooves in a rotor, pins being used to secure the tongues in the grooves. The strength of this conneotion' is limited by the shearing of the pins. provide a rotor rfastening forblading ofthis type and better distributed stresses both .in the blade root portions and in the material ofv thev rotor which cooperates withthe root portions` to hold the blades in place. To

constitutingl the side walls of It is the object of. myV inventionA to which shall involve relatively` lower.

Figi?) is afragmentary view of a' portion ofthej rotor or disc-having grooves made 1n acordance with myfinvention i Referring nowtotlie drawing fora bet-` ter understanding of invention, Ip'show a turbine disc or rotor 10,1which isprovided n with a pluralityY of circumferential undercut lslots orgrooves 11 for the reception of .Y Y'

a pluralityfof' root portions 12 carried by each of' the blades 13.'v :Wedges 14;' arearranged inl the grooves 11 toholdthe root portions inpl'acegV 3 7 i Eachv undercut oove in-the rotor has one side constituted ,by f radial "portions -15 and l16, thepoition 16'b'eingoH-set with respect to they portion-15 soras to provide a groove which is wide at the-:bottom andfa shoulder 17 for cooperation'with the top faces' of the shoulders'18 provided lon the y x root .portions 12. The other Wan. 19 of each. groove 1s inclined inwardly -The root portions 12 are vprovided withVv ovfl'lset lateral ffaces 20 and 21v fwhichlit Aagainst'the off-set vradial 'faces'. 15 'and 16,

respectively, Aiandl defineV theshoulder 18 lwhichV fits the "shoulder17.l The `opposite vportions of the roots maybe insertedin 'theA slots 11 as far `as possible andfthen VVthe this end, I provide a rotor or disc with a plurality vof undercut grooves and each blade with 'a plurality of root portions having shoulders which fit the lundercutl portions of the grooves, wedges being 'inserted' inthe grooves tovhold the root portions in place.

Apparatus made inaccordance with my invention is illustrated in the accompanying drawing, forming a part ofthis application, in which, Fig. 1 is a fragmentary sectional view showing my improved turbine blade fastening; Fig. 2l is ,a section taken along lthe line Ill-II of Figl, and

straight' face 22o`f each .root portion. is op so j posed'tof theinclined grooved wallf191and the wedges i111 areV interposed 'between ,the walls-i19vfand the root 'faces 22 in 'order to hold the root portions in place.

The maximum Widen` of am hmmmf ich l root portion is less than the minimum width of the top of each slotV 'so that the shoulder blade moved longitudinally sov that theV 'l' shoulder'portions 18 .of the root portions Y 1"/ may beV brought into cooperationjwith ythe shoulders 17 p of lth'e'groovesand the faces 2O and 21 of the root portions in contact withfthe'radialwfaces V15 and 16 of f the grooves.

root portions 12 in.` order to hold the' latter in place.

While After a blade is inserted' in this 'l Y s manner,wedges14 arev driven in behind the v, i l I I. have .particularly described ai* i plurality vof L-shaped root p'ortions'for each V blade which fit Lshapedslots in'a rotor or j; gy

disc, it is tobeunderstood that, in so far as my invention is concerned, any type of y root connection andv slotV maybe used so portions. of the rootsandof the rotor are brought into `direct cooperation to f f hold 4theblades .inplaoe J long `as Freni the foregoing," it Vvv-ill be apparent .that I have devised a orifnof blade 'fastening which is suitable` for. securing unusual- ,1y Wide 'orvinasssive blades in place Whileat thefsamegtfirne, preservinglowj stress values' Y formthefastenings.

*"While I have shown my inventionwin vbut i one form, it will be obvious to those skilled in the art that it'ianotso limited, but susceptible ofvarious. other changes andr modifications, Without "departing from the spirit thereof, and I; desire,` therefore, that only such limitations shall'fbe plaeedthereupon as are imposedjby. the priorart or as are kspeoilieally set ffo'rthi inVV the appended l vim i @1am is! if "fea ' V l. In af. turbine,the combination of av .rotor having ay plurality ofcircumferential grooves, each ofthe grooveshavingan underout side-and an inclined side,fblades provided respectively with a. vphlrality'of root z V,portions Whieh lit Vthe undercut sides of said `the inclined` sides-oisaid "grooves andi said roo' tipov rtiens.y 'f

groov'ea and Wedge means tting'between ,In` la turbine, the.. Combination-zof` a rotor having,` a A plurality l of L-shaped slots and blades,{each}fof which has apluraltyio Lesha-ped root portions fitting in tlie'slots; n 4; InfJaturbine, the -eombinationfot al rotorhaving a plurality" of'eireumterential f Y Lfshaped slots and blades,eaoh of'vwhieh has a, plurality 'of f Lv-shapedk root portions@ tting in the slots, the maximum Width of the root portions being, less than the mininiuin Width of said slots.

75. In a turbine, the vcombination oiV a and a'plu'rality of blades, eaclrot which has Vapluralitygof root portions provided With shoulders 'which fit in the undercut portions" Hof saidslots. i

6. In a turbine, the combinationV of. a rotor having: a plurality oundercut slots, blades having root portions Lariuiiggge'd in said slots and provided with shoulders which fit inthe undereut portions thereo'l, andV Wedge nieansinthe slots for holding the *shoulders inthe undercut portions'ofv said'slots.

,7. In a# turbine, the combination of a rotor having aI plurality of circumferential slots provided with kundercut and inclined side- Walls, blades having;A root portions provided-With shoulders cooperating with the undereut Walls, and Wedge means interposed between thev inclined Walls-'and saidvroot portions. .v

y8.y Inra rotor' having a plurality of oir- Vcurnlerential grooves, each of whichis conystituted by a side Wall having off-set pori tions arranged in radialplanes and vopposed Walls which are inclined and `diverge inlWardly from said radial plane Walls, blades having root,y portions provided Vwith sides formed tofit the grooved' sides arranged in olfset. radial planes, and Wedge 'means inf terposed betWeenrthe root `portions and the inrlined Walls ofsaidgrooves. 1

In` testimony' Whereofl have l'iereunto.

subseribed; nry naine y .this 12th' day of, Sept.,

vrotor*havingfa pluralityof undercut slots 1 1 RoLAN-n ipzraesililivi3. 

